The relationship of biopsy evaluations and testicular measurements to over-all daily sperm production in human testes.

Enumeration of homogenization-resistant spermatids in testicular homogenates provided a rapid and precise means of characterizing human spermatogenesis in quantitative terms. This technique was applied to simulated biopsy specimens as small as 10 mg of testicular parenchyma and yielded values for daily sperm production per gram of testicular parenchyma (DSP/gm) that were highly correlated with over-all DSP/gm values for paired testes (r = +0.86) and DSP/pair of testes (r = +0.93). In 12 autopsy cases representing a 100-fold range of sperm production rates, the average difference between DSP/gm values obtained from simulated biopsy specimens and from entire testes was not significantly different from zero (P < 0.05). The small amount of testicular parenchyma required for this determination indicated that both DSP data and routine histologic observations can be collected from the material included in a conventional testicular biopsy. Various measurements related to testicular size were positively but weakly correlated with DSP/testis (values for r ranged from +0.45 to +0.66). Hence, testicular size was a relatively poor index of sperm production in this study.